Nested if statement within for loop [JAVA/LibGDX]

So I got my code to work this more of a question in regards to Java and why it worked the way I got it VS. why it didn't work the first way I wrote it. This is the original code I wrote.

private void renderGUIExtraLives (SpriteBatch batch){
    float x = GUIcamera.viewportWidth - 50 - Constants.LIVES_START * 50;
    float y = -15;
    for (int i = 0; i < Constants.LIVES_START; i++) {
        if (worldController.lives <= i) {
            batch.setColor(0.5f, 0.5f, 0.5f, 0.5f);
            batch.draw(Assets.instance.bunny.head, x + i * 50, y, 50, 50, 120, 100, 0.35f, -0.35f, 0);
            batch.setColor(1, 1, 1, 1);
            }
        }
    }

This didn't work, it threw no errors, but it did not draw the lives to the screen, all I did was remove the curly braces of the if statement like so:

private void renderGUIExtraLives (SpriteBatch batch){
    float x = GUIcamera.viewportWidth - 50 - Constants.LIVES_START * 50;
    float y = -15;
    for (int i = 0; i < Constants.LIVES_START; i++) {
        if (worldController.lives <= i) 
            batch.setColor(0.5f, 0.5f, 0.5f, 0.5f);
            batch.draw(Assets.instance.bunny.head, x + i * 50, y, 50, 50, 120, 100, 0.35f, -0.35f, 0);
            batch.setColor(1, 1, 1, 1);
        }
    }

And now magically it worked, can some explain why it worked after I removed the curly braces from the nested if statement? I would really appreciate it, as well as any discussion regarding this topic would be great to read if someone has a link to a similar question or answer here on Stack.